Walk the Line
Kinesin (3Kin)
Outline
Structure:
-Kinesin is a type of motor protein found in eukaryotic cells
-Its structure is a dimer, it includes two heavy chains (which are called the motor domains) and two light chains (α-helical stalks)
-The image seen here is from PyMOL, and it was used to separate the individual chains/proteins from larger complexes
-PyMOL can be used to learn about molecular structures including molecular size, bond lengths/angles, and specific sites of inter/intramolecular forces (important for binding of ligands)
Conserved:
-The motor domains contain highly conserved regions, which is expected because these are the sites of microtubule and ATP (discussed later) binding.
-These regions cannot change much or binding would not commence.
Function:
-Kinesin proteins move across microtubules and its main functions include transport and motility
-The motor domains contain 2 binding sites, 1 for ATP and 1 for microtubules
-Movement along the microtubules is powered by hydrolysis of ATP to ADP
-Hydrolysis of ATP causes a conformational change which leads to “power strokes”
-Kinesintransport a wide range of structures including vesicles and organelles, and are also important in chromosome movement during cell division
Diseases:
– Spactic Paraplegia
– Polycystic Kidney Disease
– Alzheimer’s Disease
– Salmonella